Collators for folded sheets



April 21, 1959 M. NELSON ,883,185

COLLATORS FOR FOLDED SHEETS Filed Sept. 19, 1956 3 Sheets-Sheet l E IN V EN TOR.

April 21, 1959 M. NELSON COLLATORS FOR FOLDED SHEETS Filed Sept. 19, 1956 3 Sheets-Sheet 2 d VENTOR April 21, 1959 M. NELSON COLLATORS FOR FOLDED smms 5 Sheets-Sheet 3 Filed Sept. 19, 1956 MNVENTOR. BY i W HTTORNEVJ United States Patent 2,883,185 COLLATORS FOR FOLDED SHEETS Marcellus Nelson, Viroqua, Wis. Application September 19, 1956, Serial No. 610,734 14 Claims. (Cl. 270-55) This invention relates to improvements in collators for folded sheets.

Collators are employed for the purpose of assembling folded printed sheets to form booklets, pamphlets, newspapers or the like, and the present invention is particularly useful in assembling small newspapers such as small-town papers or shopping news publications, where one side of each folded sheet is longer than the other so that there is an overhang.

Heretofore collators have been expensive and have utilized suction cups or friction devices for picking up sheets. Furthermore, in ordering these devices ithas heretofore been necessary to specify a definite number of "sheets to be assembled, as collators now generally available cannot be used to assemble a greater number.

It is a general object of the present invention to prov idea less expensive device than those now on the market, which device provides anentirely mechanical operation without use of suction cups or friction devices.

further object of the invention is to provide a collator which has unlimited capacity in that sets of assembled sheets may be run through the machine additional times to assemble additional sheets thereon depending upon the number of pages desired for the completed booklet.

A more specific object of the invention is to provide a collator which includes a row of hoppers, one behind another, all of the pages of a publication which bear the same numbers being stacked in the same hopper, and the stacks in the several hoppers being so arranged that the first hopper contains those pages which fit into the center of the completed booklet; there being mechanical means engaged within the fold for withdrawing the bottommost folded sheet from the first hopper and for carrying it within the bottommost folded sheet of the next hopper to remove the latter and so on, until a booklet has been assembled; and there being multiple assembling operations which take place simultaneously on the machine.

With the above and other objects in view, the invention consists of the improved collator for folded sheets, and all of its parts and combinations, as set forth in the claims, and all equivalents thereof.

In the accompanying drawings illustrating one complete embodiment of the preferred form of the invention, in which the same reference numerals designate the same parts in all of the views:

Fig. 1 is a perspective view of a collator showing a number of completed booklets in the receiving receptacle at the discharge end;

Fig. 2 is a sectional view taken approximately on the line 2-2 of Fig. ,1;

Fig. 3 is a sectional view taken on the line 3-3 of Fig.2;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2;

Fig. 5 is a partially diagrammatic view in longitudinal section similar to Fig. 2 showing one foldedsheet which has been previously removed from a preceding hopper being inserted within another folded sheet; and

Fig. 6 is a view similar to Fig. 5 showing two folded sheets engaged by the rod just after the rod (has advanced beneath and beyond the forward wall of the hopper from which the last sheet has been removed.

Referring more particularly to the drawings, there is a suitable supporting frame including spaced longitudinally extending side members 10 and 11 which may be supported on legs 12. The side members are suitably connected by transverse spacer members 13, and suitably supported on top of the spacer members by nuts and bolts 14, are longitudinally extending angle members 15 having upstanding sides. Spanning the bases of the angle members 15 are sheet draping forms 16 preferably constructed of sheet metal, on which lower parts of bottommost sheets are adapted to drape themselves by gravity. Each includes a horizontal portion 17 which is tight against the bases of the angle members 15 an upwardly inclined portion 18, and a top portion 19 which is inclined upwardly at a slight angle. The forward edge of the top portion 19 joins the top of an upright forward wall 20. There are a plurality of sheet draping forms, one in front of the other, throughout the length of the machine.

Endless chains 21, one on each side of the device, have oppositely disposed upstanding cars 22 at intervals throughout the length of the chain to support the ends. of transverse sheet pickup rods 23. Both ends of each rod project laterally beyond the ears 22 as at 24.

The endless chains travel around suitably mounted sprocket wheels including the sprocket wheels 25 of Fig. 1 which are rigidly mounted on a drive shaft 26. One end of the drive shaft may have a pulley 27' or equivalent member mounted thereon to receive power from an outside source or the shaft may be driven by a suitable motor attached to the machine. For small models it is entirely practical to rotate the shaft 26 manually by means of a crank or other instrument.

Each chain travels relatively close to the inner surface of one of the guides 10 or 11 as shown in Figs. 3 and 4. The projecting ends 24 of the rods 23 are adapted to engage and travel along the upper surfaces of inclined rails 28. These rails are best shown in Fig. 2. There is -a series of sets of rails, one set for each hopper.

Suitably pivoted at one end to transverse rods 29 which extend between the side members 10 and 11 are bars 30 having free end portions which are adapted to rest upon the pick-up rods 23. Springs 31 coiled around the ends of the rods 29 are connected to the pivoted ends of the bars 30 to yieldingly urge the outer ends of the bars in a downward direction. As long as a bar 30 is resting on a pick-up rod 23, and as long as the latter is supported on inclined rails 28, the bars 30 cannot move in a downward direction. As soon, however, as a rod such as the rod 23 of Fig. 2 passes the ends 32 of a set of rails the tensioned bars 30 will cause the rod to snap down- Wardly, there being a certain amount of play in the endless chains 21, until the bars contact the resilient. bumpers 33. This downward movement of a rod 23 is enough to allow it to pass beneath the forward edge of a hopper as in Fig. 6 and as will be hereinafter described in greater detail.

Each hopper comprises a rear upstanding wall 34 and a front upstanding wall 35. The rear wall has its ends flanged forwardly as at 36 and the lower portions of said flanges are suitably connected to the side rails as shown in Fig. 3. Spaced inwardly from each of the flanges 3'6 and also projecting forwardly from the wall 34 are vertical sheet engaging strips 37. The lower edge of each rear wall 34 has a forwardly extending paper supporting ledge 38 (see Fig. 2).

The front wall 35 of each hopper has rearwardly projecting end flanges which are suitably secured to the side walls 10 and 11 of the frame (see Fig. 4). The lower edge of each of the walls 35 is upwardly slotted at spaced points as at 40. Suitably secured to the front side of each wall 35 are resilient paper holding strips 41, one for each of the slots 40. Each strip has its lower portion free and in registration with a slot 40. The extreme lower end is bent at an obtuse angle rearwardly as at 42 (Fig. 2) to project rearwardly through the slot 40. These bent portions 42 releasably support the folded forward portions of the sheets in the hopper, as is shown in Fig. 6. It is obvious from Fig. 6 that urging the fold line portion of the bottommost sheet in a downward direction may cause the spring strips 41 to yield forwardly slightly so that the lowermost folded sheet can clear the lower edge of the bent portions 42 to pass beneath the lower edge of the wall 35. Said yielding movement is insufficient to release the sheets thereab ove.

The frame projects forwardly beyond the forwardmost hopper, and extending transversely between the forwardly projecting portions of the side members 10 and 11 is a table 43 which is in a plane below the lower edge of the wall 35 of the forwardmost hopper. Projecting upwardly from said table are yielding kicker fingers 44. These fingers have their inner ends secured to the table 43 below the forward wall of the forwardmost hopper. The free ends of the fingers extend forwardly and upwardly for a substantial distance as shown in Fig. 1. When a pickup rod passes forwardly from a position beneath the lower edge of the wall 35 of the forwardmost hopper within the fold of an assembled paper, the rod with the papers thereon will press the forward portions of the yielding fingers 44 down to approximately horizontal position until the rod passes beyond the forward ends of the fingers. At this point the pickup rod will be about ready to pass downwardly around the sprocket wheels 25, and as it approaches this position the yielding fingers 44, freed by the rod, will resiliently snap upwardly to the position shown in Fig. l, kicking the rear portion of the assembled newspaper in an upward direction so that the assembled paper can then slide by gravity off of the descending bar into the receiving receptacle 45.

Operation In operation, folded sheets of paper, usually printed, such as the sheets 46 of Figs. and 6 are placed in the hoppers with their fold lines 47 facing forwardly. The fold line is so located that the top page projects rearwardly as at 48 beyond the rear edge 49 of the lower page of the folded sheet, and it is to be noted that the rear edge 49 is forwardly of the flange 38 at the lower edge of the rear wall 34 of a hopper. All of the folded sheets which are to be in the center of the finished booklet or newspaper are placed in a stack in the rearmost hopper of Fig. 1. All of the sheets which are to be next to the center are placed in a stack in the next hopper, and so on, the outer or cover sheets being in the forwardmost hopper. The lower portion of the bottommost folded sheet in each hopper, due to its short termination at 49 will fall by gravity to the position A shown in Fig. 5 to drape over the inclined portion 18 and top portion 19 of a sheet metal draping form 16. Thus each bottommost sheet will be supported in a V formation with the open portion facing rearwardly, ready to receive a pickup rod 23.

When the shaft 26 is driven, the endless. chains 21 and pickup bars will start to move. The pickup bar 23 which is nearest to the rear hopper will pass underneath the flange 38 of the rear wall 34 of the rearmost hopper, and the projecting ends 24 of the pickup rod will be guided upwardly on the upper surfaces of a set of rails 28 as shown in Figs. 2 and 4. As. the rod approaches the forward ends 32 of the rails 28 it will be engaged by the spring urged bars 30 as shown in Fig. 2. When the ends 24 of the rod 23 pass the forward ends of that set of rails 28 which is below the rearmost hopper, the rod will be approximately within the fold of the bottommost folded sheet. Also when this occurs the spring urged pressure from the bars 30 will snap the rod downwardly with the bottommost folded sheet so as to position the leading folded edge below the inwardly angled lower ends 42 of the yielding fingers 41 to a position beneath the lower edge of the forward wall 35 of the hopper. This down- Ward movement of the pickup rod 23, when its ends fall off of the ends 32 of the inclined rails 28, is permitted because there is sufiicient slack in the endless chains. The downward movement is limited and cushioned by engagement of the spring urged bars 30 with the bumper blocks 33. During such movement the yielding strips will yield enough to release the fold line of the bottommost sheet without freeing the sheets thereabove.

The rod 23 with the folded sheet therein now passes below the forward wall 35 and into the open V of the bottommost folded sheet of the next hopper as shown in Fig. 5, ready to intercept said folded sheet in the same manner, the rod ends 24 riding up another set of inclined rails until permitted to drop as heretofore described in connection with the previous hopper. Thereafter the pickup rod will pass beneath the forward wall 35 with two folded sheets assembled thereon as shown in Fig. 6. This will continue until a folded sheet from each hopper has been assembled on the rod.

As shown in Fig. 1 there are multiple puickup rods 23 spaced apart the same distance that the hoppers are spaced from one another. Thus every pickup rod behind the one just described is also assembling folded sheets in the same manner, so that the machine delivers assembled newspapers or booklets in rapid order.

As heretofore described, each assembled paper, as it passes beneath the lower edge of the forward wall 35 of the forwardmost hopper, is guided on top of the kicker fingers 44 to depress the latter until the pickup rod clears the ends of said fingers. Thereafter the fingers will spring up to the position of Fig. 1 to kick the rear of the assembled paper to a raised position so that the paper can fall by gravity from its pickup rod before the latter returns for another trip.

If it is desired to assemble newspapers or booklets having more sheets than the number of hoppers in the machine, then at the end of a run the assembled papers from the receptacle 45 may be placed in the rearmost hopper, with additional folded sheets to be assembled placed in order in the other hoppers. Then the bottommost one of the partially assembled papers in the rear hopper will have all of its lower pages, due to the shortness thereof, fall by gravity onto the sheet metal shelf 16 just as the single page of a single folded sheet does in Fig. 5. Thus the next pickup rod to enter the rearmost hopper will pickup a group of sheets and will assembleadditional sheets thereon as the pickup rod travels forwardly. It is apparent that there is no limit to the number of times that a partially assembled publication may be run through the device, and hence there is no limit to the number of sheets which may be assembled. Heretofore it has been necessary to order machines for a specified number of folded sheets, and any publication having pages in excess thereof could not be assembled by the machine.

It is apparent from the above that the device is very simple and that it has few parts to get out of order or out of adjustment. It is also apparent that the machine is relatively foolproof in operation and can speedily assemble sheets without limit as to capacity.

Various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within the scope of the claims.

What I claim is:

l. A collator for folded sheets which each have a top part and a shorter bottom part with said top part having a free edge projection which projects beyond the free edge of the shorter bottom part comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of superimposed folded sheets each in a substantially horizontal plane and with the fold lines facing forwardly, a horizontal ledge at'the bottom of each hopper of a length to engage the free edge projection only for supporting one edge of the upper part of the bottommost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, means including a releasable holder exteriorly engageable beneath the fold line portion of said bottommost sheet to normally support said portion, and means including a pickup member mounted for movement in a generally horizontal direction beneath the hoppers longitudinally of the line of hoppers and engageable in sequence with the fold lines of said opened bottom sheets to progressively pull them from said releasable holders and assemble a pluralityof sheets, one within another.

2. A collator for folded sheets comprising a plurality of open'bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottommost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, said means including a downwardly projecting spring holder having a bent lower end engageable beneath the fold line, and means including a pickup member mounted for movement beneath the hoppers longitudinally of the line of hoppers and engageable in sequence with the fold lines of said opened bottom sheets to progressively pull them from the spring holders and assemble a plurality of sheets one within another.

3. A collator for folded sheets comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottommost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, said means including a releasable spring holder engageable with the fold line, means including a pickup member mounted for movement beneath the hoppers longitudinally of the line of hoppers and engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, and means for causing a downward displacement of said pickup member after it is in position within a fold line to pull the engaged sheet from the spring holder to a position below the open bottom of the hopper so that the sheet may thereafter be advanced with said pickup member.

4. A collator for folded sheets comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottommost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, said bottom part being of less length, a sheet draping form below each hopper on which said bottom part of a bottommost sheet is adapted to rest to be held in draped position, and pickup means mounted for movement beneath the hoppers and longitudinally of the line thereof and above said draping forms, said pickup means being engageable in sequence within the fold lines of said open bottom sheets to assemble a plurality one within another.

5. A collator for folded sheets which each have a top part and a shorter bottom part comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, each hopper having a back wall with a bottom flange for supporting the rear edge of the upper part of the bottommost folded sheet while allowing the rear edge of the shorter bottom part to fall by gravity so that the folded sheet is open, and each hopper having a front wall, means on said front wall including a releasable holder engageable with the fold line of bottom sheets, and pickup means mounted for movement beneath the hoppers and longitudinally of the line thereof engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, said releasable holder being responsive to movement of said pickup means for releasing its engagement with the fold line of the bottommost sheet.

6. A collator for folded sheets which each have a top part and a shorter bottom part with said top part having a free edge projection which projects beyond the free edge of the shorter bottom part comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of superimposed folded sheets each in a substantially horizontal plane and with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottommost folded sheet while allowing the bottom, part to fall by gravity so that the folded sheet is open, endless means mounted for movement beneath the hoppers and longitudinally of the line of hoppers, longitudinally spaced transverse nods supported by said endless means so that each rod is engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, and inclined slide means, below each hopper positioned to be engaged by the rods to guide them upwardly toward the fold lines and having endsfrom which said rods may fall by gravity after av sheet has been picked up whereby the rods may advance in a lower position toward the next hopper.

7. A collator for folded sheets comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottommost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, endless means mounted for movement beneath the hoppers and longitudinally of the line of hoppers, longitudinally spaced transverse rods supported by said endless means so that each rod is engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, inclined slide means below each hopper positioned to be engaged by the rods to guide them upwardly toward the fold lines and having ends from which said rods may fall after a sheet has beenpicked up whereby the rods may advance in a lower position toward the next hopper, and downwardly yielding rod engaging means for each hopper positioned to engage a rod from above and to urge it downwardly after the rod leaves the end of said inclined slide means.

8. A collator for folded sheets comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottommost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, endless means mounted for movement beneath the hoppers and longitudinally of the line of hoppers, longitudinally spaced transverse rods supported by said endless means so that each rod is engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, inclined slide means below each hopper positioned to be engaged by the rods to guide them upwardly toward the fold lines and having ends from which said rods may fall after a sheet has been picked up whereby the rods may advance in a lower position toward the next hopper, a pivotally mounted bar below each hopper positioned to engage a rod from above, and yielding means for urging each bar in a downward direction to snap an engaged rod downwardly after it leaves the end of said inclined slide means.

9. A collator for folded sheets comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets withrthe fold lines facing forwardly, means at the bottom 7 of each hopper for supporting the upper part of the bottomm'ost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, endless means mounted for movement beneath the hoppers and longitudinally of the line of hoppers, longitudinally spaced transverse nods supported by said endless means so that each rod is engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, inclined slide means below each hopper positioned to be engaged by the rods to guide them upwardly toward the fold lines and having ends from which said rods may fall after a sheet has been picked up whereby the nods may advance in a lower position toward the next hopper, a pivotally mounted bar below each hopper positioned to engage a rod from above, yielding means for urging each bar in a downward direction to snap an engaged rod downwardly after it leaves the end of said inclined slide means, and bumper means positioned to stop the fall of each bar.

10. A collator for folded sheets comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of folded sheets with the fold lines facing forwardly, means at the bottom of each hopper for supporting the upper part of the bottomrnost folded sheet while allowing the bottom part to fall by gravity so that the folded sheet is open, endless means having upper and lower stretches mounted for movement beneath the hoppers and longitudinally of the line of hoppers, rods supported by said endless means so that each rod of the upper stretch of said endless means is engageable in sequence with the fold lines lOf said lopened bottom sheets to assemble a plurality one within another, means for causing a shout downward movement of each rod after it is in position within a fold line to move the engaged sheet to a position below the open bottom of the hopper so that the sheet may thereafter be advanced with said pickup nod, upwardly and forwardly projecting yielding fingers in advance of the forwardmost hopper positioned to be depressed by each pickup rod as it passes over said fingers, the forward end of said endless means being immediately in advance of said fingers whereby when said depressed fingers are freed by a rod the trailing portions of sheets on the rod are kicked upwardly so that the sheets may fall from the rod by gravity as the rod moves from the upper to the lower stretch of said endless means.

11. A collator for folded sheets which each have a top part with said top part having a free edge projection which projects beyond the free edge of the shorter bottom part and a shorter bottom part comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of superimposed folded sheets each in substantially a horizontal plane and with the fold lines facing forwardly, means at the bot-tom of each hopper of a length to engage the free edge projection only for supporting one edge of the upper part of the bottommost folded sheet while allowing the shorter bottom pant to fall by gravity so that the folded sheet is open, means including a releasable holder engageable beneath the fold line portion of said bottommost sheet to normally support said portion, and means including a pickup member mounted for movement in a generally horizontal direction beneath the hoppers and longitudinally of the line thereof engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another.

12. A collator for folded sheets which each have a top part with said top part having a free edge projection which projects beyond the free edge of the shorter bottom part and a shorter bottom part comprising a plurality of open bottom hoppers supported in line formation, each hopper being adapted to contain a stack of superimposed folded sheets each in a substantial horizontal plane and with the fold lines facing forwardly, means at the bottom ofeachhopper. of a length to engage the free end projection only for supporting one edge of the upper part of the b-ottommost folded sheet while allowing the shorter bottom part to fall by gravity so that the folded sheet is open, means including a releasable holder engageable beneath the fold line portion of said bottommost sheet to normally support said portion, means including a pickup member mounted for movement in a generally horizontal direction beneath the hoppers and longitudinally of the line thereof engageable in sequence with the fold lines of said opened bottom sheets to assemble a plurality one within another, and means for causing a short downward movement of said pickup member after it is in position within a fold line and simultaneous release of said releasable holder to move the engaged sheet to a position below the open bottom of the hopper so that the sheet may thereafter be advanced with said pickup member.

13. A collator for folded sheets which each have a top part and a shorter bottom part with said top part having a free edge projection which projects beyond the free edge of the shorter bottom part comprising a plurality of open bottom hoppers supported in line formation and each having a rear upright wall and a forward upright wall, each hopper being adapted to contain a stack of superimposed folded sheets each in a substantially horizontal plane with their fold lines facing forwardly, said rear wall of the hopper having a ledge at its lower edge of a length to engage only said free edge projection of the upper part of the bottommost folded sheet while allowing the shorter bottom part to fall by gravity so that the folded sheet is open, at least one releasable holder on the lower portion :of the forward wall of each hopper having a p:ortion exteriorly engageable beneath the fold line of the bottomrnost folded sheet, and means including a pickup member mounted for movement in a generally horizontal direction beneath the hoppers longitudinally of the line of hoppers and engageable in sequence with the fold lines of said opened bottom sheets to progressively pull them from said releasable holder and assemble a plurality of sheets one within another.

14. A collator for folded sheets which each have a top part and a shorter bottom part with said top part having a free edge projection which projects beyond the free edge of the shorter bottom part comprising a plurality of open bottom hoppers supported in line formation and each having a rear upright wall and a forward upright wall, each hopper being adapted to contain a stack of superimposed folded sheets each in a substantially horizontal plane with their fold lines facing forwardly, said rear wall of the hopper having a ledge at its lower edge of a length to engage only said free edge projection of the upper part of the bottommost folded sheet while allowing the shorter bottom part to fall by gravity so that the folded sheet is open, at least one yieldable finger on the lower portion of the forward wall of each hopper having a bent lower end projecting inwardly of the hopper and engageable beneath the fold line :of the lowermost folded sheet, and means including a pickup member mounted for movement in a generally horizontal direction beneath the hoppers longitudinally of the line of hoppers and engageable in sequence with the fold lines of said opened bottom sheets to progressively pull them off of said spring fingers and assemble a plurality of sheets, one within another.

References Cited in the file of this patent UNITED STATES PATEN 'L'S 937,925 Christensen 1 "Oct. 26, 1909 1,043,401 Coy Nov. 5, 1912 1,659,099 Halvorsen Feb. 14, 1928 1,766,117 Ellsworth June 24, 1930 1,774,580 Wich Sept. 2, 1930 2,021,360 Halvorsen Nov. 19, 1935 2,709,584 Kleinberg May 31, 1955 

